Transcript for Snapped Fastener Thought to Have Caused Circus Accident

details coming in on that strange terrifying circus accident. Thousands of adults and children watching. Eight young women plunged 35 feet during a startling act. The women hanging by their hair. ABC has on what happened. Reporter: The shocking sight. Eight women hanging only from their hair. Twirling high above a circus crowd. Today federal officials investigating how it could go so horribly wrong. Watch again. This is the ringling brothers legend show in Rhode Island Sunday. Just as the curtain dropped, 4,000 people in the audience would see this happen. Those eight women falling more than three stories, the giant contraption that held them aloft crashing on top of them. The crane was heavy. It took ten guys and you could see them struggling to lift it from atop of the girls. Reporter: Watch as the cable breaks free. Tonight investigators have zeroed in on the metal piece called a carabiner. That failed. It was a single piece of equipment that failed. Reporter: Remember, these performers are working without a net. Watch this rehearsal video. Ten rotations in just five seconds. Experts say a head of human hair is strong enough to support 12 tons. Nobody saw a net under the performers. Is that standard that there wouldn't be a net under there? This act is not performed with a net. They're attached by their hair. They performed this act over 150 times. Reporter: Tonight eight performers remain in the hospital. One of them whitny, a third generation circus performer. Her father by phone. She's okay. She's doing okay. Only has a broken arm. And some fractures of the neck and back, too. Reporter: He told us his daughter is of the circus and expects she'll be back under the big top. Gio Benitez, ABC news, Providence, Rhode Island.

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